Can anyone with a FSM please scan the pinout and any description of the N* igntion system?

I have a project for my LT1 and want to see if I can use N* parts to make it with.

Thanks!!

STS-in-Nottingham

01-02-07, 12:41 PM

These are 1998 STS

N0DIH

01-02-07, 01:19 PM

Thank you very much! It shows 4 connectors, do you have the last one?

Odd that they only use a 24x resolution? Is that the low res or high res? The LT1 use a 360 res and uses rising edge and falling edge on the square wave, so that makes it 720 degrees res. Very high, I would expect the N* to be similar too.

Thanks!!

STS-in-Nottingham

01-02-07, 01:38 PM

For some reason, the other connector is not shown.

As for the rest of your post, it's way over my head!!, "high res,low res" ?????,....means nothing to me.

Sounds like you have an interesting project, good luck with it and I hope I've been of some help.

.

N0DIH

01-02-07, 01:44 PM

Pretty simple, GM uses a "high res" signal for the high crankshaft position accuracy. And the low res is to identify where #1 is. So if 24x is high res and 4x is low, then it will have 24 even slots that produce a square wave that shows where the crankshaft absolute position is (likely 48x if they use the rising edge of the waveform and trailing edge like the LT1 does), the 4x low res typically will consist of 4 different width slots, say 10 degrees, 20, 30 and 40 (guessing here!) and the PCM will find out very quickly which one passed by its sensor and know exactly which cyl to start firing.

Simple eh?

So, what I want to do is make this, http://www.gmhightechperformance.com/tech/0310htp_lt1_ignition_system_understanding_modifyin g/ work with the N* ignition module. I am concerned that I will lose accuracy though, the LT1 system is VERY VERY accurate.

Thanks!!

MonzaRacer

01-02-07, 11:27 PM

Ok the first thing is that the Northstar/Aurora V8 DIS you have to have the N*/Aurora "wheel" as it has 24 even teeth and 8 uneven and you need the cam sync signal too. A typical 32 tooth wheel will not mak it function ALSO the DIS module uses dual crank sensors split by 27 degrees for "quick start" feature which allows the module/computer to actually see and start within 90 degrees of rotation. The signals come out of the module conditioned and produced by the module.
Now I am in the process of building the crank sensor adaptor (its at machine shop now) and uses very simple VR sensors that are very small and after I get the crank wheels built then it will be a simple bolt on to adpat to other cars. I have done this on a 4 cylinder S10 with other parts and I do have a friend who is using 2, 4 cylinder DIS Modules running a small block chevy and is still trying to combine the output signals for computer use so he doesnt have to use 2 computers.
Un fortunately this module was never designed to run with single crank signal or a "standard" trigger wheel.
I know of one company that already has a "fix" kit for a trashed LT1 dist. as long as the one sync signal still operates it is a plug and go.
The Company is called Delteq or Deltec and was actually features in one of the car mags as an option to replaceing the problem ridden Optispark.
Oh and I do believe the other connector is the second crank sensor.
Here is a link to some beginning research for using the N*/Aurora DIS but please be careful as this DID olnly sorks on N*/Aurora crank wheels and dual sensors and this diagram might have the rest of the information you are looking for.I have the Mitchel pinouts somewhere as I am still perfecting the V8 adpatable DIS kit and it SHOULD provide proper signal to the stock computers with little or no problems (as GM designed most of thier ingnition modules to make same signals so techs didnt have to learn a 100 different patterns).
Hope fully I will get my brackets and wheels in this month so I can start the matching of parts.
http://megasquirt.sourceforge.net/extra/setup-gmdis.html
Look at the bottom as it shows the N* crank signal, trust me it is a bitch to copy.

N0DIH

01-03-07, 12:19 AM

I actually am not going to try to add trigger wheels, but simply take the high res signal that the Opti puts out and down sample it to the high res the N* ignition module uses. 360/15=24 The LT1 uses what I believe (not sure yet, need more info on the N* low res) is nearly the same if not the same as the N* low res. So that may make it a pass through signal only.

Yes, Delteq. They are charging $800 for it. WAAAY too much for a signal converter, 4 coils and an igntion module.

As for me, the Opti has proven reliable, so there isn't a reason to replace it, but it would be nice to go with the LS1 coil type setup, which will be the ultimate goal. For now the N* setup will work too.

My concern is the Opti is far more accurate than the N*'s ignition, but is it enough to be a "problem"? Likely not.... The Opti uses a optical sensor with 360 openings that they measure the rising edge and trailing edge to get a total of 720 degrees of resolution. Likely the N* module does the same, looks for 24 pulses and measures rising and falling edge of them to make 48x.

eldorado1

01-03-07, 12:51 PM

I don't think you understand how the crank sensor/northstar DIS system works.

The DIS module CREATES the 24x and 4x signals. It does not get them from the PCM or something....

The DIS module does this by using the center crossings of the crank sensors. Yes - sensors (two). The crank trigger wheel is not just a wheel with 24 notches cut into it. It has an extra 8 notches spaced like 1...2...2...3 evenly across the wheel. Saying you're going to "adapt" an optispark signal for a northstar DIS module without using a microprocessor is ludicrous. The DeltEQ module has one. It's not just a box of resistors and flip flops, it is microprocessor controlled. That's why it costs so damn much - they had to pay a team of engineers to program it.

In addition, from what I've been hearing from SBC owners who have been trying to use the Northstar DIS module... it is EXTREMELY sensitive. These are people who have laser cut trigger wheels attached to their harmonic balancers. They say if ONE crank sensor is 0.5 degrees off, it won't fire. Half a degree!

N0DIH

01-03-07, 01:21 PM

How does the DIS module CREATE the 24x and 4x? Where does it come from then? The crank trigger wheel....

I don't NEED it that way, I will be able to combine it from the Opti info, which is far more detailed. Don't worry... I know far more about than most. I just don't have the N* FSM to reference, which I need. This module was based on the Buick 3300/3800 modules, which I have studied in detail.

eldorado1

01-03-07, 05:02 PM

I'm still confused as to how this is going to work, so I'm just going to take a stab at it here. Tell me if I'm close....

You are going to turn an optispark wheel into a trigger for a northstar DIS module. In doing so, you'll need to "fill in" (solder/braze/weld) the wheel gaps to match the northstar crank trigger (or laser cut a new one), and double it because the cam rotates at 1/2 crank speed. In addition, you will install a second pickup to duplicate the second crank sensor on the northstar.

You'll then use the 24x output from the DIS module to run the PCM?

N0DIH

01-05-07, 09:20 AM

No, I am going to use the high accuracy of the Opti info, and convert it to what the N* module requires (it has to know where #1 is, which is the unequal slots, and it needs to have the high res for the crank position). The LT1 uses 2 discrete signals, which would need to be combined to make the N* DIS happy.

I still have a lot of info to pour over, to see what the DIS needs to make it happy. Like you said, accuracy, small amount off can cause problems.

By no means is this a toss together thing. If I need a uP for it, no problem, we can do. The Motorola HC11 is a sweet one, still available, and can be had in Automotive grade (this is a big deal if mounted underhood). I know, I came from the Automotive group at my company. (hint, if you have OnStar, my fingers have been all over the cell phone side....).

I'll try to do up a block diagram

clarkz71

01-05-07, 12:01 PM

Yes, Delteq. They are charging $800 for it. WAAAY too much for a signal converter, 4 coils and an igntion module.

.

Well the module & coils alone are around $600. Are you telling me that another $195 isn't a good deal for a complete kit, ready to install? And the $785 isn't just for a signal conveter, 4 coils and a module.

No, I am going to use the high accuracy of the Opti info, and convert it to what the N* module requires (it has to know where #1 is, which is the unequal slots, and it needs to have the high res for the crank position). The LT1 uses 2 discrete signals, which would need to be combined to make the N* DIS happy.

I still have a lot of info to pour over, to see what the DIS needs to make it happy. Like you said, accuracy, small amount off can cause problems.

By no means is this a toss together thing. If I need a uP for it, no problem, we can do. The Motorola HC11 is a sweet one, still available, and can be had in Automotive grade (this is a big deal if mounted underhood). I know, I came from the Automotive group at my company. (hint, if you have OnStar, my fingers have been all over the cell phone side....).

I'll try to do up a block diagram

OK for the most part you are trying to bark up a tree that isnt a tree. As for building your own system go for it but if you simply build a Megasquirt and put a simple triger wheel on the crank and use the box to run ignition (I do believe either MSD or Mallory or Accel has a rplacement distributor for optispark, but if the cap/rotor still work then you can add one of those systems but I dont have any info on that.
As for the Delphi module it was set up to run the irregular cut wheel on the N*/Aurora crank and a cam sync signal and it manufacures its reference pulces for the computer. ALL GM modules use the ignition module to "condidtion " the signals. OH and the ingition module uses VR signals and 2 sensors 27 degrees apart so you need to remember this but its simply a matter of making the proper bracket/sensor assembly and trigger wheels and then all ya gotta do is use the cam drive to run a #1 sync signal and you can run DIS and the computer SHOULD never know the difference. BUT one thing you gotta make sure of is that the Camaro set up causes knock retard signals that can be piped into the module or you will have a car that will keep advancing the igniton till it maxes out.
My plan is a cam sync signal coming from a Dist plug that runs the oil pump from the cam. And I figure the bracket I designed will place my DIS inplace of the distributor. The crank wheel is fun part.
Lee

N0DIH

01-23-07, 05:18 PM

I finally got my 99 P12 Motorhome chassis FSM (yes, I am a FSM junkie) in the mail and after looking at it, there is no desire whatsoever to use the N* Ignition module. And seeing the Pricetag of it didn't help either! I sure hope that module is dead nuts reliable for that price.

The 99 L29 454 uses the coil on plug like the LS1 and L18 496/8100 BB. It would be far easier to adapt that system to an LT1 than use the N* ignition module.

The slick part of the coil on plug is they are coils with essentially thier own ignition module on the coil, so all it takes is a simple low voltage signal to trigger it. This likely could be easily adapted to the N* with not too much issue. It is very simple. Worse come to worse, build a Megasquirt to control just ignition and leave the rest to the PCM and then you have some timing controls....

MonzaRacer

01-27-07, 10:12 PM

Here is what I found,

MonzaRacer

01-27-07, 10:35 PM

Well I have actually been working on the control block design to use the COPs in a Megasquirt system. The big thing I like about the DIS with the N* module is thatthe module conditions all of the signals that MS needs. My thoughts on using one was for the fact it was an actual part available from a parts store.
The system I was working on with the COPs was a pair of coil drivers wired as in paralel to fire 2 COPs coils as wasted spark system till I figure out the sequential end (or they finish some more coding for sequential on the MS sight.) as right now all they have are 6 outputs to run 12 cyl in wasted spark.
I have also been working out a bolt on dual crank sensor to fit a SBC/BBC and a bolt on crank wheel copied from the N* crank wheel.
I also have the oil pump drive/cam sensor plug in the machine shop to be finished.
As I have been told one coil driver will control 2 COPs as one fella has a dual plug engine running that way and no problems.
The only thing that is limited on the MS is that it isnt sequential FI ,,,yet.
The other good thing is that if pretty much anything in it blows you can probably look them up locally or at local electronics repair shop as the totla parts list is like ony 80 to 100 bucks.
Anyway hope the attached pic came through and helps.
Lee